SQL Server with Mr. Denny


May 24, 2017  7:00 PM

Should I build a 1×6 VM or a 6×1 VM?

Denny Cherry Denny Cherry Profile: Denny Cherry
SQL Server, Virtual Machines

TaskManagerThis sort of question comes up a lot. And there’s a lot of it-depends built into the answer, so I’ll try and break this down a little bit for you. Be warned, we’re going to be talking about NUMA and other hardware-y things here for the most part.

Standard Edition

You wants 1×6 (one socket, 6 cores) because standard edition will only use the first 4 sockets in a server (up to 16 cores combined). There’s no getting around that.

From a NUMA perspective as long a vNUMA at the Hypervisor is disabled then it doesn’t matter as SQL Server standard edition isn’t NUMA aware (NUMA awareness is an Enterprise Edition feature).

Enterprise Edition

This is where things get more complicated if vNUMA is enabled in VMware or Hyper-V.

vNUMA Enabled

If vNUMA is enabled then you want one multiple vSockets and multiple vNUMA nodes so that SQL Server is aware of how the CPUs and memory are laid out within the hardware so that SQL can made good decisions on how the processes are being laid out against the hardware.

Now that said, you probably don’t want 6 vSockets. You probably want 2 vSockets with three cores each so that you get multiple cores per vSocket. But a lot of that will depend on if you can control how many vSockets there are per vNUMA node.

vNUMA Disabled

If vNUMA is disabled then you care less because SQL thinks that everything is in a single NUMA node so it’s going to make decisions based on that.

More RAM than a pNUMA node

If the amount of RAM configured for your VM is larger than a physical NUMA node, then you need to turn on vNUMA for the VM (no matter how many cores you have) and configure the VM to the cores equally across the NUMA nodes that you present to the VM.

WTF?

Yes, this is all very hardware-y, and requires some understanding of how pNUMA, vNUMA, vSockets, etc. all work together. For most DBAs you’ll want to just kick this over to the VMware / Hyper-V admin and have them do some tweaking.

May 17, 2017  4:00 PM

Is there anything different in Azure with Elastic Pools when it comes to management?

Denny Cherry Denny Cherry Profile: Denny Cherry

Short answer, “no”.Cloud

Long answer:

From a management perspective Azure SQL DB and Azure Elastic Pools are the same.  As far as the DBA or the developer is concerned they are the same.  Think of Elastic Pools as a billing construct.  With SQL DB (not in Pools) you pay for X amount of performance for each database.  With Elastic Pools you pay for D performance for E databases and each database gets at most F performance.

Billing

So lets say I buy a Standard Elastic Pool with 800 eDTUs.  I can put up to 500 databases in there and they are going to share that 800 eDTUs.  Each database can have up to 100 eDTUs per database before it’s going to have it’s performance throttled.

The idea behind the elastic pools is that the performance profile for each database will be different, and they won’t need to spike to their limit all at the same time. If they did that would be a performance problem as you’re run out of DTUs to spread across the databases.  In this example pool basically 8 databases can hit 100% of their DTU limit before everyone suffers.

The reason that you’d want to setup things this way is from a pricing perspective. An 800 eDTU pool is going to cost you ~$1800 a month.  A single 100 DTU standard database will cost you ~$150 a month.  If you have more than 12 databases that all need to cap out at 100 DTUs, and their performance profiles aren’t the same (the have their spikes in workload at different times) then putting them in an elastic pool will be cheaper.

Management

From a management perspective databases in a SQL DB and outside a SQL DB are basically the same.  Everything that’s supported inside a normal SQL DB is supported inside an Elastic Pool database.  They have the same features and limits. The big difference is that the performance limits are now a shared pool of resources not dedicated per database.

For DBAs who are used to working with instances on-prem this should be a familiar pattern for you.  Think of an Elastic Pool as a SQL Instance on a server.  The server is a pool of resources that you have to decide what databases to stick inside that pool.  It’s the same idea here. The difference between on-prem and in Elastic Pools is that in Azure you don’t know how many cores or RAM you have, you just have the eDTU construct.  And you can have multiple Elastic Pools per Azure SQL Server name (something.database.windows.net).

Monitoring

For monitoring you have the same options between Azure SQL DB and Elastic Pools. You can use the Azure portal, you can query the API using PowerShell or the CLI. Or you can use DB Sentry from SentryOne (SQL Sentry) to monitor things just like you used to.

Denny


May 12, 2017  11:11 PM

Patch your Machines Now. Stop working on other stuff and patch stuff, NOW

Denny Cherry Denny Cherry Profile: Denny Cherry

There is a massive crypto worm running around the internet destroying computers and networks.  You need to patch your machine. The reason that patching is so

Screenshot of the CryptoWare

Screenshot: MalwareHunterTeam (via Gawker)

important to get protected from this work, is that this worm doesn’t require that you click on anything to attack you. Once it’s in your companies network it can start hitting machines around the network that aren’t patched and it could, depending on your patching settings, encrypt every machine in your network.

This is bad.  In just a day 45,000+ computers have been encrypted.

In case you missed it, patch … NOW!!!!!!

If you want to read up, this is the security hole that you need to fix.

This page from Microsoft shows how to ensure that you are fully patched.

It’s Mothers Day in the US this weekend, so you’re going to call Mom anyway. Tell her to patch her computer.

Denny


May 10, 2017  5:10 PM

Microsoft announces MySQL as a Service

Denny Cherry Denny Cherry Profile: Denny Cherry
https://www.flickr.com/photos/theaucitron/5810163712/

https://www.flickr.com/photos/theaucitron/5810163712/

Today at Microsoft’s //build conference Microsoft announced a couple of new data platform services that are available for people who are looking to run MySQL driven applications using Microsoft’s cloud in a Platform as a Service (PaaS) solution. This solution gives you the same flexibility and ease of management of the other PaaS data platform solutions that Microsoft has made available in their offering, but now with a fully Open Source platform.

In addition to the MySQL platform they also announced PostgreSQL as an open source offering in their PaaS offering. While the PostgreSQL announcement is just as huge, I’m focusing on the MySQL announcement as that’s the part of the platform that I’ve been working with as it hosts WordPress.

Why?

Why would Microsoft be putting these open source offerings? Because they’ve been on the roadmap for quite some time. Remember that a large portion of Azure is running open source software and platforms for customers. But moving those open source platforms into a PaaS offering is quite a bit harder than just standing up a couple of VMs and calling it a PaaS platform. There’s a massive amount of tooling and automation that has to happen on the back end to configure all this, plus setup the portal to handle management, as well as the integration with all the other components in Azure (OMS, firewall, monitoring, alert rules, etc.)

Now I know that some people are going to drone on and on about how this is just Microsoft reacting to Google’s announcement back in March. And that couldn’t be further from the truth. Microsoft has been working on this service for months and it’s been in Private Preview since long before Google’s announcement. I know this because several of our websites have been using this service as the database backend for months now.

What you get when you spin up a MySQL (or PostgreSQL) database in this new PaaS service is a MySQL instance with HA built into the platform. You just connect to it like you would any other MySQL service by using the MySQL command line tools (or any of the web based management tools) and you create databases and point your applications at them.

Is it complete?

My assumption (and hope) is that the goal for these open source PaaS Data Platform services is parity with the SQL Server based solutions. So as this platform gets closer and closer to GA we’ll hopefully see this service getting closer and closer to the parity in features between the SQL Server based data platform solution and the MySQL based solution.  Personally I can’t wait for multi-site configurations to be available to we can stretch a MySQL database across multiple sites, then I’ll have to come up with a plugin that’ll redirect read only queries to another database server in a MySQL configuration which’ll be kind of cool to work on.

This sure is an exciting time to be working in Data Platform especially in Azure as Microsoft brings us more Open Source Software into the Azure stack.

Using MySQL in PaaS

DCAC has been using this MySQL in PaaS solution for quite a while now, since probably sometime in January to run several of our sites, including the development version of our main website where we do some WordPress plugin development.  We put the dev site there because when doing development and testing of WordPress plugins you end up generating a lot of controlled workload for a server so you can see everything that’s coming up and being a problem.  And frankly it’s been pretty easy to forget that this is a private preview service.

The response time for an OLTP application (which was what we were testing) was really good.  The database queries were a few milliseconds longer than when the MySQL database was running locally, and that’s all because of the network difference between talking to a VM in the same subnet and talking to a service in the same region, but that’s understandable and acceptable.  Going across regions introduces the expected level of network latency that you’d get going across the network from one city to another.  As this service is lit up in more regions this problem will become less and less as you’ll be able to have MySQL databases in the same region as your web servers.

All in all we’ve been very happy with the service as we’ve been using it against development and customer facing websites over the last several months.  And we’re really looking forward to see what Microsoft gives us with the product in the coming weeks and months so that we can eventually move all our sites to it and stop managing VMs in Azure.

Denny


May 8, 2017  4:00 PM

Your Redgate Winners of an Amazon Echo Are…

Denny Cherry Denny Cherry Profile: Denny Cherry

Back in March Redgate kicked off a contest on a few blogs to give away some SQL Clone licenses and some Amazon Echo Dots.  That contest has come to a close, SQL Clone Logoand Redgate has announced the winners of the contest. So if you entered on the DCAC blog post, Joey’s post, or any of the other pages go check out Redgate’s post announcing the winners to see if you’ve won the Echo and a license.

(I believe there will be other posts from Redgate in the future that’ll have the winners of SQL Clone in them, I’m not really sure how they’re announcing them.)

Go check out their post, and check out SQL Clone as well with their free trial.

Denny


May 3, 2017  4:00 PM

Solving performance problems after large data change occurs

Denny Cherry Denny Cherry Profile: Denny Cherry
SQL Server

If you’ve worked with SQL Server for any period of time you’ve problem run into what appear to be pretty random occurrences of SQL Server starting to have performance problems which go away after you rebuild the indexes. What’s going on to make the problem happen, and what’s solving the problem are however not what they appear.

When this happens the common thought it that it’s index fragmentation that is causing the problem. And while that isn’t helping you, it isn’t the root cause of the issue.

In most situations, however the cause of the problem is out of date statistics. And the solution is to update the statistics, or more specifically have SQL Server update them more often automatically.

If you are running SQL Server 2008 R2 SP1 through SQL Server 2016 then you want to turn on trace flag 2371 when SQL Server status (you can set it as a startup parameter, and then turn it on by running DBCC TRACEON (2371, -1) and that’ll make it take effect until the next restart).  There’s really no downside to this trace flag being on, especially for systems that have large amounts of data change impacting query performance. The only negative impact that this trace flag will have is that the system will trigger update statistics more often throughout the day. To ensure that this doesn’t cause problems we also need to enable async auto stats updates.

After you’ve made these changes, you’ll need to update statistics as update stats won’t trigger right away, and the problem shouldn’t return.

Denny


April 26, 2017  4:00 PM

Partitioned Tables and ColumnStore

Denny Cherry Denny Cherry Profile: Denny Cherry

ColumnStore indexes are all the rage with data warehouses. They’re fast, they’re new(ish) and they solve all sorts of problems when dealing with massive amounts of data.  However they can cause some issues as well if you aren’t very careful about how you setup your partitions on the ColumnStore index.  This is because, you can’t split a ColumnStore partition once it contains data.

Now, if everything is going according to plan you create your partitions well in advance and there’s no issues.

However, if everything hasn’t gone according to plan and someone forgets to create the partitions and you end up with rows in the final partition, you can’t create any more partitions because you can’t split the partition.

We can see this pretty easily with a quick repro.

CREATE PARTITION FUNCTION myRangePF1 (int)
AS RANGE LEFT FOR VALUES ( 1, 100, 1000 );
GO

create partition scheme myScheme1
as partition myRangePF1
all to ([primary])

create table t1
(c1 int)
on myScheme1(c1)

create clustered columnstore index cs on t1 on myScheme1(c1)

insert into t1
(c1)
values
(1), (10), (100), (600)

With our table here we’ve got a partition function with break points at 1, 100, and 1000. We then insert rows into a columnstore index on that table with the values of 1, 10, 100 and 600. If we try and split our partitions using the ALTER PARTITION FUNCTION command with any value between 1 and 1000 we’ll get an error message.

ALTER PARTITION FUNCTION myRangePF1 ()
SPLIT RANGE (500);

This is because those partitions contain data. If we try and more any of the partition ranges (1, 100, or 1000) then we’ll get an error because we can’t merge them together either.

So how to be work around this issue? Well the easiest way is to delete the data from the table, then fix the partitions, then put the data back. And frankly, that’s the only option. There’s a variety of ways to do that. The easiest option is probably to partition switch out that partition to an un-partitioned table. Then it’s just a matter of moving that data back into the partition in question.

Now if the partition that you’re currently writing to is the last partition, and you need to keep writing to that partition while this is all happening thing are going to get a little more interesting as you’ll need to take an outage in order to do all this work. There’s really no good solution besides taking an outage to move data around and get it correct in order to resolve this issue.

I wish I had a better answer here, but so far there’s no good solution.

Denny


April 19, 2017  3:00 PM

Correcting the Outbound Email Address for Office 365 Users When Using AD Connect

Denny Cherry Denny Cherry Profile: Denny Cherry
Office 365

That’s one hell of a long title isn’t it? I ran across a little issue in our Office 365 account recently. That problem was users having the wrong outbound email address in Office 365. I was trying to figure out why a new account that I had setup in our dcac.co domain kept showing up in Outlook at username@dcassoc.onmicrosoft.com instead of username@dcac.co.

Well the reason that it was showing up this way was because that’s how Office 365 was configured, of course. Now when I create a user (we’ve never had Exchange on prem, so we can’t see any of the Exchange tabs) I setup the account for the user, let it sync to Azure and added the licenses and didn’t think anything of it.

Later I saw the issue. Fixing it is pretty easy, if you know where to look.

Fixing it before the user is in AAD

If you are creating a new user in AD, making it so that the account is created correctly is actually pretty easy.ad1

In the properties of the user, fill out the email address field in the users account. This will tell Azure Active Directory and Office 365 that the users outbound email address should be whatever you put in that field (assuming that it’s a domain that you have control over).

If the users account has already synced to Azure as you discover this problem, this won’t fix it (or at least it didn’t for me).

In the testing that I did, using this field to fix it only works on account creation.  But that’s ok, it’s still a pretty easy fix to fix this after the user has had their account synced to Azure.

Here’s what the user account looks like in Azure after the initial sync has completed with the email field blank.

office1

Fixing it after the user is in AAD

If the user is in AAD, and Office 365’s Exchange properties shows the user as the onmicrosoft.com account, all is not lost. You don’t need to do anything drastic like deleting the user or anything.

In a domain controller, probably the one with AD Connect installed on it, open Active Directory Users and Computers.  Click on View then Advanced Features.

Now go find the problem user and open their account.  You’ll see a new tab called “Attribute Editor”, select it.  Scroll down until you find the proxyAddresses field.  It’s probably listed as “<not set>”. That’s fine, we’re going to fix this.  This proxyAddresses field is how we tell Azure and Office 365 (and Exchange) what the email addresses are that the user can receive email as, and what email address is their outbound email address.Setting outbound email address in Active Directory

If we edit that we’ll get a dialog that allows use to add items to the list. Now don’t just add in email addresses, that isn’t going to work.  You can list all sorts of items in there.  Specifically we want to add in our SMTP addresses.  We do this in the format of smtp:username@domain.com.  In the case of our test user it’ll be testuser@dcac.co.  Now we can put in as many email addresses as we need them to get email at.  So how do we set the outbound email address?  We make the “smtp” part uppercase.

If you are a company that changes users email addresses when then change their name (they get married or divorced for example) then you’ll want to keep their old email address in there.  So you just set it as “smtp:oldname@domain.com” in all lowercase.

In the screenshot we’ve two SMTP addresses, username@dcac.co with the upper case SMTP and oldname@dcac.co with the lowercase SMTP.  This allows the user to received email on both username@dcac.co and oldname@dcac.co while sending any outbound emails as username@dcac.co.

office2If I go look at the list of accounts which the user has, you’ll now see that the SMTP in upper case is the bolded one (that’s how Office 365 shows which email is the outbound).  And if we look at the user in the mailbox list we’ll now see that the email address has changed from username@dcassoc.onmicrosoft.com to username@dcac.co.

office3

A fairly easy change, and no impact to the user, other than the impact that we wanted, which is that the users email address is now correct and matches the companies branding. It’ll take a while at this point for the users email address to be corrected in everyone’s Global Address List (GAL). It’ll take a little time, the GAL doesn’t update that often, but when it gets around to updating the users will all get the update.

Using PowerShell to fix things in bulk

This change can be made in PowerShell as well. In this case I’ve setup the PowerShell to only for against a single user, but you can setup the -Filter parameter anyway you need to in order to get things working the way you need.

$users = Get-ADUser -Filter {UserPrincipalName -eq 'testuser@dcac.co'} -Properties SamAccountName, ProxyAddresses, UserPrincipalName
$users | Foreach {
Set-ADUser -Identity $_.SamAccountName -Add @{Proxyaddresses="SMTP:"+$_.UserPrincipalName} -whatif
}

I’ve left the -whatif in there so you can see what it’ll do before running it. You’ll want to be careful running PowerShell against your Active Directory domain as you can really screw things up if you aren’t careful. Be warned, if you already have values in this ProxyAddresses field, this will simply append to them. If there’s a default in there you’ll now have two and Office 365 will get cranky. So you may need more logic and checking in your script. But I’ll leave that to you.

If you are planning a cloud migration, or you have already started one, be sure to contact DCAC.  We are one of the premier experts in cloud migrations, frequently training other consulting companies on how to perform cloud migrations.

Denny


April 12, 2017  2:00 PM

ZyXEL with client VPN and Azure Site to Site VPN Configuration

Denny Cherry Denny Cherry Profile: Denny Cherry
Azure, VPN

I’m going to start out by saying that I’m not a networking guy, at all. But that said sometimes I have to pretend to be a networking guy. In our lab we have a decent set of machines. We also have our Azure environment that’s up and running which is where our websites, etc. are all running out of. To keep things simple we have our VPN setup at the CoLo as that’s where we need to go most of the time when we’re VPNed in since that’s where we can spin up servers for free.

Ever since we setup the CoLo we have had this annoying issue of having to RDP to a VM in the CoLo before being able to talk to Azure. It isn’t a major thing, but it’s gotten annoying. Eventually I got sick enough of it to try and fix it.

4 hours later I had a solution.

Now we have a ZyWall 110 but this should be similar for most of their hardware. The first thing I needed to do what add another address object. That address object needs to be able to cover all the networks inside the network as well as the subnet that you’re using to give IPs to your VPN clients. Our CoLo is 172.30.0.0/21 and we’re using 172.30.250.0/24 for our VPN endpoints. Because I’m lazy it setup as 172.30.0.0/16.  This is going to be needed later on.  I’ve got another address object named “Azure-US-West-Production” that defines our IP Subnet for our Azure Virtual Network.

subnet

Once that’s created you’ll need to modify the VPN Connection to use the new address object as the local policy.

vpn_policy

When this was done the VPN dropped, so I had to tell the VPN to reconnect (or allow it to reconnect by itself).

Once that’s done you’ll need to add a route to direct the network traffic to where it needs to go.  For the route, you’ll need to setup the Incoming as “Tunnel”, then select the tunnel that your users VPN through (we use L2TP over IPsec and our tunnel is named ClientVPN).  For the source address I left that as “any”. For the Destination I selected the subnet for the Azure vNet that I want to allow people to connect to.  In the Next-Hop section Change the type to VPN Tunnel and select the correct VPN Tunnel that connects to the correct vNet. In my case it’s called Azure-USWest-Production.

policy

We have several vNets in Azure (4 to be specific) and we want to be able to access all of them directly, so I had to repeat this for each one of them.

Now users that are VPNed in are able to access the VMs in Azure directly from their desktops and laptops without having to RDP to a VM in the CoLo.

Denny


April 5, 2017  4:00 PM

Compare Plans in Query Store

Denny Cherry Denny Cherry Profile: Denny Cherry

Have you ever been looking at an execution plan in the SQL Server Query Store reports and wanted to be able to see what the differences between that plan and another plan were?

Did you know that you can?

It’s a couple of step process, but you can compare the plan in the Query Store to any plan that is saved as a “.sqlplan” file.  Simply right click on whatever plan you want to compare to (either a real plan, estimated plan, or plan from the query store) and click “Save Execution Plan As” and save the plan to your local hard drive.  Then locate the plan you want to compare in the Query Store.  Right click on that plan, and select “Compare Showplan”.

That’ll give you a pretty GUI like the one shown below (click to enlarge).  By default anything shaded in red in both plans will be identical. Anything not shaded you’ll want to look at as those are different in some way.  Looking at my queries below you’ll notice that they look the same. What’s different on these is actually the costs, row counts, etc.

compareYou’ll also notice the two sets of properties with the little yellow not equal too signs next to them. That tells you which values from the properties don’t match.  That’ll give you a quick easy visual identifier as too what is different between the two execution plans.

Personally I’d like to just be able to right click on a couple of the plans in the Query Store and compare them without saving, but I didn’t see a way (doesn’t mean there isn’t one, or that there won’t be one in the future).

Denny


Forgot Password

No problem! Submit your e-mail address below. We'll send you an e-mail containing your password.

Your password has been sent to: